Apparatus for assigning spare areas for defect management and apparatus for handling fragmented ECC blocks

ABSTRACT

A recording medium having a spare area for defect management, and a method and apparatus for allocating and assigning the spare area. A plurality of zones are formed as one group without prescribing the relationship between a zone and a group. Spare areas include a spare area for slipping replacement and a spare area for linear replacement. The spare are for slipping replacement is first allocated, and the spare area for linear replacement is allocated according to the size of an area remaining after the spare area for slipping replacement is used and the purpose for which a disc is used. When the spare area for linear replacement becomes deficient during use of the disc, a supplementary spare area for linear replacement is allocated in sequence from the rearmost of a logical file area, such that the spare area can be more flexibly and effectively allocated.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application Nos. 98-42433,filed Oct. 10, 1998; 98-44202, filed Oct. 21, 1998; 98-47538, filed Nov.6, 1998; and 99-17357, filed May 14, 1999 in the Korean Patent Office,the disclosures of which are incorporated herein by reference. Thisapplication is a continuation of U.S. patent application Ser. No.10/334,008, filed Dec. 31, 2002 now U.S. Pat. No. 6,879,553, currentlypending, the disclosure of which is incorporated by reference, which isa divisional application of U.S. patent application Ser. No. 09/609,821,filed Jul. 3, 2000, which issued as U.S. Pat. No. 6,697,307, which is acontinuation-in-part of U.S. Ser. No. 09/415,916, filed Oct. 12, 1999,which is issued as U.S. Pat. No. 6,747,929.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to the field of optical recording media,and more particularly, to a disc having spare areas for defectmanagement, and an apparatus for allocating and assigning spare areasand for handling fragmented ECC blocks.

2. Description of the Related Art

In order to manage defects on a general recordable/rewritable disc,slipping replacement for skipping defects without providing logicalsector numbers to the defects, is used for defects (primary defects)generated upon initialization of the disc, and linear replacement forreplacing error correction code (ECC) blocks of an erroneous zone withnormal blocks in a spare area, is used for defects (secondary defects)generated during use of the disc.

That is, slipping replacement is used to minimize a reduction in therecording or reproduction speed due to defects, in which a logicalsector number to be provided to a sector which is determined to bedefective during a certification process for inspecting defects of adisc when the disc is initialized, is provided to a sector next to thedefective sector, that is, data is recorded or reproduced by slipping asector where a defect is generated during recording or reproduction.Here, an actual physical sector number is shifted by the sector numberdesignated by skipping the defective sector. Such a shifting-backwardsphenomenon is solved by using as many sectors as there are defects in aspare area located at the end portion of a corresponding recording area(group or zone). According to the specifications, the position of adefective sector replaced by slipping replacement is prescribed to berecorded in a primary defect list (PDL) in a defect management area(DMA) on a disc.

Slipping replacement cannot be used for a defect which is generatedwhile a disc is being used. When a defective portion is disregarded orskipped, discontinuity is introduced into the logical sector numbering,which means that slipping replacement violates file system rules. Thus,linear replacement is used for defects generated during use of the disc,in which an ECC block including a defective sector is replaced by an ECCblock existing in a spare area. The location of the defective blockreplaced by linear replacement is prescribed to be recorded in asecondary defect list (SDL) in a defect management area on a disc. Whenlinear replacement is used, logical sector numbering is not interrupted.However, when there is a defect, the positions of sectors on a disc arediscontinuous, and real data for a defective ECC block exists in a sparearea.

Meanwhile, a digital versatile disc random access memory (DVD-RAM)according to the DVD-RAM standard version 1.0 is comprised of aplurality of groups each having a user area and a spare area which areconstant in each zone. FIG. 1A is a half plan view of a disc showing auser area a guard area and spare area, and FIG. 1B one-dimensionallyshows several zones on a disc. Each zone is comprised of a guard area, auser area, a spare area, and a guard area which are sequentiallyarranged.

A disc is segmented into zones to solve inaccurate recording due to achange in the speed of a spindle during recording and to use a zoneconstant linear velocity (ZCLV) method in order to increase the searchspeed with respect to a constant linear velocity method.

That is, when defects are managed by the linear replacement, ifpossible, linear replacement within a defective zone increases thesearch speed since there is no change in the linear velocity of a disc.Thus, the DVD-RAM allocates a certain amount of spare area to each zoneas shown in FIG. 1B, to accomplish linear replacement.

In this existing defect management method, each zone acts as a group,and a spare area is allocated at the end of each group. Each group ismanaged as a defect management area. Also, since the start sector numberof each group is predetermined, an ECC block is supposed to start at thestart position of a zone which is a unit for physically segmenting anarea.

The start logical sector number of each group is designated as describedabove. Thus, when defects are managed by slipping replacement, slippingreplacement must be performed only within a corresponding group. Inorder to replace defects generated in a corresponding group using theslipping replacement, the number of defective sectors that are slippedmust be less than the number of usable sectors in a spare area in thecorresponding group. Accordingly, a restriction that a large defectgenerated in one group must be processed within the group limits themaximum size of a defect that can be replaced by the slippingreplacement.

If the size of defects to be replaced by slipping replacement is greaterthan the size of a spare area in a corresponding group, a spare area inanother group must be used by linear replacement. However, when linearreplacement is used, defects are managed not in units of sectors but inunits of ECC blocks, that is, in units of 16 sectors. Thus, a spare areaof 16 sectors is required to process one defective sector, whichdegrades the efficiency of defect management.

Also, a standard size of a spare area for defect management ispredetermined, so that spare areas of the same size must be alsoallocated in applications to which defect management using linearreplacement cannot be applied, such as real time recording. Therefore,the efficiency of area utilization of a disc is degraded.

SUMMARY OF THE INVENTION

To solve the above problems, it is an object of the present invention toprovide a recording medium which generates a plurality of zones as onegroup and has a spare area allocated in advance for slipping replacementfor a group and a spare area allocated later for linear replacement.

It is another object of the present invention to provide a method ofefficiently and flexibly allocating spare areas by generating aplurality of zones as one group, allocating a spare area for slippingreplacement in advance, and allocating a spare area later for linearreplacement.

It is another object of the present invention to provide an apparatus toefficiently and flexibly allocate and assign spare areas by generating aplurality of zones as one group, assign a spare area for slippingreplacement in advance, and assign a spare area later for linearreplacement.

It is another object of the present invention to provide an apparatus toefficiently and flexibly allocate and assign spare areas by generating aplurality of zones as one group, assign a spare area for slippingreplacement in advance, assign a spare area to prevent fragmentation ofblocks at zone boundaries, and assign a spare area later for linearreplacement.

Accordingly, to achieve the first and other objects, the presentinvention provides a recording medium which forms a group out of aplurality of zones on a disc, the group including a user data area andhas a primary spare area allocated to the generated group.

To achieve the second and other objects, the present invention providesa method of allocating a spare area for a disc recording and/orreproducing apparatus which allocates the spare area for disc defectmanagement, the method comprising the step of forming a group out of aplurality of zones on a disc, the group including a user data area, andallocating a primary spare area for slipping replacement to thegenerated group.

To achieve the third and other objects, the present invention providesan apparatus assigning a spare area for a recording medium, theapparatus assigning the spare area for disc defect management by forminga group out of a plurality of zones on a disc, the group including auser data area, and by assigning a primary spare area for slippingreplacement to the generated group.

To achieve the fourth and other objects, the present invention providesan apparatus assigning a spare area for a recording medium, theapparatus assigning the spare area for disc defect management by forminga group out of a plurality of zones on a disc, the group including auser data area, and by assigning a primary spare area for slippingreplacement to the generated group, assigning an additional spare areato skip blocks at boundary zones, and assigning a secondary spare areafor linear replacement to the generated group.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and advantages of the present invention willbecome more apparent by describing in detail a preferred embodimentthereof with reference to the attached drawings, in which:

FIG. 1A is a half plan view of a conventional disc having a user area, aguard area and a spare area, and FIG. 1B shows the one-dimensionalstructure of several zones of a conventional DVD-RAM disc;

FIGS. 2A and 2B are views for explaining allocation of spare areas uponinitialization according to an embodiment of the present invention, andFIG. 2C is a view for explaining allocation of spare areas during useafter initialization;

FIGS. 3A and 3B are views illustrating the discontinuity of an ECC blockwithin zones by a defective sector upon slipping replacement;

FIG. 4 is a flow chart illustrating a method of allocating spare areasduring initialization according to the embodiment of the presentinvention; and

FIG. 5 is a flow chart illustrating a method of allocating spare areasduring use after initialization according to the embodiment of thepresent invention.

FIG. 6 is a block diagram of a recording/reproducing apparatus forimplementing the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Spare areas on a disc for defect management according to the presentinvention include a primary spare area, a secondary spare area and asupplementary spare area.

The primary spare area is first allocated for defect replacement when adisc is initialized, and is first used for slipping replacement. Aportion of the primary spare area remaining after slipping replacementcan be used as a secondary spare area for linear replacement. Thesecondary spare area, for linearly replacing defects generated duringuse of the disc, denotes the area remaining after the primary spare areais used for slipping replacement during initialization. The secondaryspare area can also denote a separately-allocated spare area. Thesupplementary spare area, for linearly replacing defects generated whilethe disc is being used, denotes another spare area additionallyallocated.

That is, in the present invention as shown in FIG. 2A, a plurality ofzones on a disc forms a group, and a spare area (primary spare area) forslipping replacement is first allocated at the end of each group duringinitialization. Each group includes a user data area. The user data areacorresponds to a remaining area of the group, exclusive of a primaryspare area, a secondary spare area and a supplementary spare area, asshown in FIG. 2C. The slipping replacement performs replacement in unitsof sectors, thus increasing the efficiency of utilization of the sparearea. However, in the slipping replacement, defective areas are merelynot used, and data starts being recorded in the next normal sector, sothat the defective areas cannot be used after initialization.

During initialization, as much spare area as possible is allocated asthe primary spare area for slipping replacement, but the primary sparearea remaining after slipping replacement can be used as a secondaryspare area for linear replacement. When it is determined that linearreplacement cannot be sufficiently performed by using only the secondaryspare area allocated within the primary spare area after slippingreplacement is completed upon initialization of a disc, a secondaryspare area for linear replacement can be allocated to each zone as wellas a portion of the primary spare area, as shown in FIG. 2B. Thesecondary spare area has no logical sector number, and information onthe secondary spare area allocation is stored in and managed by a defectmanagement area (DMA). The secondary spare area allocated duringinitialization is essentially disposed at the end of a zone, though thesecondary spare area is not necessarily allocated in every zone. Sincethe spare area for linear replacement is allocated at the end of a zone,it is easily controlled. Also, since the spare area is controlled inunits of a zone, a spare area in a zone closest to where a defect isgenerated can be easily found. Furthermore, modification of existing DMAinformation can be minimized.

The secondary spare area can be disposed before a guard area which isthe last part of a zone. When the secondary spare area is disposed ineach zone, its size can be predetermined as a relative size or anabsolute size according to a numerical expression (for example, 3% ofeach zone).

While a disc is being used after being initialized, when a spare areafor linear replacement allocated in units of zones is insufficient, apredetermined amount of supplementary spare area for linear replacementis allocated starting from the highest portion of a logical file area ina file system, as shown in FIG. 2C. The user data area, which isexclusive of the primary spare area, the secondary spare area and thesupplementary spare area in the physical area of FIG. 2C, denotes a filesystem having file list information and a logical file area. Duringlinear replacement, the supplementary spare area is used in reverseorder starting from the rearmost of the logical file area, thus solvingdiscontinuity of the logical file area.

Linear replacement is performed in units of ECC blocks, so that anentire spare area of an ECC block is used even when one sector isdefective. In the linear replacement, a defective block is replaced by aphysically-isolated spare area, so that the search speed is lowered whena defective zone is searched for. However, the linear replacement canrespond to defects generated while a disc is being used, so that it isused with respect to secondary defects generated during use of the disc.

Just as much supplementary spare area as the size of an empty continuousarea at the rear of the logical file area is allocated. The maximum sizeof the supplementary spare area must be smaller than the area of a finalzone. Here, the logical file area denotes a logical area among the totalarea used in a file system, where a user data file can berecorded/reproduced.

In a disc having a diameter of 80 mm, the radius of a user data areamust be 38 mm at the most since the 80 mm-diameter disc is affected byrapid double refraction from around a 38 mm radius due to injection of adisc.

When a spare area for slipping replacement is allocated at the end of adisc by forming a group out of a plurality of zones according to thepresent invention, a spare area having a size large enough to beprocessed in a group is allocated for, at most, 7679 items (for fifteensectors), which are the maximum number of defects that are processedusing a primary defect list (PDL). In this case, a spare area (a sparearea used for controlling block positions) must be further allocated toprevent an ECC block from not starting at the start position of a zonedue to the shifted-backwards phenomenon of the logical sector number atthe boundary between zones caused by slipping replacement.

For example, when a disc applied to the present invention is a 1.46 GB(Giga Bytes) DVD-RAM, a primary spare area allows PDL entries for eightsectors and 64 SDL entries to be processed, thus preventing thegeneration of a warning immediately after formatting due to a lack ofprimary spare area. Here, the warning level is generated when a sparearea is smaller than 32 ECC blocks.

A PDL entry that can be processed by the primary spare area correspondsto between one sector and eight sectors, and an SDL entry is for betweenone sector and eight sectors. A spare area for processing the PDL entry(S_(PDL)) and a spare area for processing the SDL entry (S_(SDL)) can beexpressed by the following Inequality 1:1≦S_(PDL)≦8; and 1≦S_(SDL)≦8  (1)

The shifted-backwards phenomenon of the logical sector number due toslipping replacement, which can occur at the boundary between zones,will now be described with reference to FIGS. 3A and 3B.

In a group formed of a plurality of zones as proposed by the presentinvention, when a defective sector exists in a zone #n as shown in FIG.3A, remaining sectors not forming an ECC block unit are located at theend of the zone due to slipping replacement. When data is written to theremaining sectors not forming an ECC block unit, the shifted-backwardsphenomenon of the logical sector number due to slipping replacementoccurs at the boundary between zones, so that discontinuity of an ECCblock can be generated at the boundary between zones as shown in FIG.3B. That is, one ECC block can be located over two zones. In this case,problems can occur, in that a disc must be driven at different speeds toread or write one ECC block located over two zones, and a user area anda guard area must be separately processed since a physical sector numberis continuous between them. The guard area is a buffering area forpreventing driving from becoming unstable due to the difference in therotating speed between zones.

In the present invention, when less sectors than the number of sectors(16 sectors) for forming one ECC block remain at the end of a zone dueto generation of defective sectors, they are not used and skipped. Asize as large as expressed by the following Equation 2 must be allocatedto a spare area used for controlling an ECC block to start at the startposition of a zone in response to the shifted-backwards phenomenon of alogical sector number that may occur at the boundary between zones dueto slipping replacement:spare area for block position control=(number of zones−1)×(number ofsectors for each error correction block−1)  (2)

In a DVD-RAM disc, an ECC block has 16 sectors, so that a maximum of 15sectors can remain at the end of a zone if an ECC block does not startat the beginning of a zone. Remaining sectors at the end of each zonewhich do not form an ECC block, must also be skipped in order to matchthe start position of an ECC block with the start position of a zone, sothat a spare area as large as the skipped sectors is further required.The number of boundaries between zones is obtained by subtracting onefrom the number of zones. That is, where there are two zones, the numberof connection portions between zones is one, and where there are threezones, the number of connection portions between zones is two. A sparearea for block position control which is as large as one ECC block, canbe substantially allocated to each zone.

Thus, it is preferable that one disc has only one group for slippingreplacement. In this case, a spare area for slipping replacement can beallocated at the end of the disc in consideration of the number ofentries that can be processed using PDL and SDL, and the size of a sparearea (here, a maximum of 32 ECC blocks) for controlling the startposition of an ECC block on the boundary between zones.

In this way, a plurality of zones are set as one group, and a spare areafor slipping replacement is allocated at the end of the group. Thus,degradation of the capability to cope with a burst error generated by alarge scratch is suppressed due to the small size of a spare areaallocated in each group when there are a plurality of groups each havinga plurality of zones.

For example, in a disc of about 4.7 GB capacity having one group in eachzone, one group includes about 1600 tracks, and the width of each trackon a physical disc is about 1 mm, as shown in FIG. 1A. When a scratchlarger than 1 mm is generated on the disc in the radial direction, about1600 sectors become defective. However, if a group is formed of one zoneand a spare area is allocated at a certain ratio according to thecapacity of the disc, it is determined that only about 1100 sectors canbe slipping-replaced at the inner circumferential portion of the disc.Hence, about 400 to 500 remaining sectors cannot be replaced by slippingreplacement, and are replaced by linear replacement instead. In thiscase, about 400 to 500 ECC blocks for spare areas are required, and theperformance of the disc at a zone where the corresponding defect isgenerated is greatly degraded. However, when a large spare area isallocated with respect to the entire disc for slipping replacement asproposed by the present invention, slipping replacement can even beperformed with respect to such a large defect.

FIG. 4 is a flow chart illustrating a method of allocating spare areasto a disc during initialization according to an embodiment of thepresent invention. Referring to FIG. 4, when an initialization commandis received in step S101, one group is formed of a plurality of zones ofa disc in response to the initialization command, and a primary sparearea is allocated at the end of the group, in step S102. That is, theprimary spare area for slipping replacement includes a spare area fordefect management with respect to 7679 data sectors (480 ECC blocks),where 7679 is the maximum number of defect management entries that canbe processed using PDL, and a spare area (here, a maximum of 32 ECCblocks) for synchronizing the start position of an ECC block with thestart position of each zone. Slipping replacement causes misalignment ofthe start sector of an ECC block at the start position of each zone, asshown in FIG. 3A. This misalignment causes fragmentation in the ECCblock which is located at the zone boundary. It is preferable not to usesuch a fragmented ECC block. To avoid using a fragmented ECC block, anadditional spare area is necessary to skip the fragmented ECC block.

Meanwhile, in a 1.46 GB DVD-RAM disc, the primary spare area can processPDL entries for 8 sectors and 64 SDL entries, and is allocated infurther consideration of the spare area for block position control.

When the primary spare area is allocated, a determination is made withrespect to the entire disc area as to whether a defect is generated, anda generated defect is replaced by slipping replacement using the primaryspare area allocated at the end of the group, in step S103. Here, if theprimary spare area allocated while the defect is being replaced byslipping replacement is insufficient, the corresponding disc isdetermined to be defective, and a step for generating an initializationerror message can be further included to prevent the disc from beingused.

When slipping replacement is completed in step S103, the portion of theprimary spare area not used during slipping replacement is allocated toa secondary spare area for linear replacement in step S104. Secondaryspare areas for linear replacement can be allocated to each respectivezone as well as a portion of the primary spare area. Informationassociated with allocation of the secondary spare areas for linearreplacement allocated to each zone, respectively, is stored in a defectmanagement area (DMA) on the disc. When allocation of the primary sparearea, and allocation of the secondary spare areas for linear replacementare completed, initialization is completed. It is preferable that thesecondary spare area within the primary spare area used for linearreplacement, and the secondary spare area allocated to each zone areused in reverse order from the rearmost of the respective secondaryspare areas to unify a method of managing a supplementary spare area forlinear replacement.

FIG. 5 is a flow chart illustrating a method of allocating spare areaswhile a disc is being used after it has been initialized, according toan embodiment of the present invention. When the size of the secondaryspare area for linear replacement allocated during initialization of adisc is insufficient to replace defects generated during use of theinitialized disc, a supplementary spare area for linear replacement isallocated.

In FIG. 5, a determination is made as to whether a supplementary sparearea for linear replacement is required during use of the disc, in stepS201. If it is determined that the supplementary spare area is required,a determination is made as to whether a sufficient amount of continuousempty area exists at the rear portion of a logical file area, in stepS202. If it is determined in step S202 that a sufficient amount ofcontinuous empty area exists at the rear portion of the logical filearea, a supplementary spare area of a predetermined size is allocatedfor linear replacement starting from the rearmost portion of the logicalfile area, in step S203, and the step S201 is again performed.

Allocation of the supplementary spare area corresponds to redistributionof a logical file area generated after initialization, so the help of afile system is required. In this case, the supplementary spare area forlinear replacement is not allocated to each zone but can be allocated inthe direction from the rearmost of a logical file area, that is, from anarea having the highest logical sector number in a logical file areawhere files can be recorded for user data, to an area having a lowerlogical sector number. When a secondary defect is generated and isreplaced by the thus-allocated supplementary spare area by linearreplacement, the search speed is barely degraded, but generation of alogical sector number area in the logical file area, that the filesystem cannot use, can be prevented. That is, discontinuity of thelogical sector number can be prevented.

In a defect management method for existing linear replacement, adefective ECC block must be replaced by the first normal ECC block thatis not used among ECC blocks within a spare area, so that defectiveblocks within the spare area are not managed even while the spare areais used in sequence from the head and the defective spare area isskipped. In this case, the spare area is allocated to each zone forslipping replacement and linear replacement. At this time, a group isformed of one zone, and thus, a plurality of groups are formed in aplurality of zones. However, in the case that blocks in thesupplementary spare area are sequentially used from the head as in theexisting method, a problem occurs when the supplementary spare area isfurther increased. That is, whenever the size of the supplementary sparearea increases, information on the increased supplementary spare areamust be separately managed. To solve this problem, blocks in thesupplementary spare area are used in reverse order from the rear. Hence,if only the highest sector number from which the supplementary sparearea starts, and the lowest sector number is detected, the entiresupplementary spare area can be continuously managed. That is, arecording and/or reproducing apparatus does not need to know how often asupplementary spare area of a predetermined size is allocated, and canmanage the supplementary spare area only if the start and end positionsthereof are recognized. However, the maximum size of the supplementaryspare area must be smaller than a final zone.

If it is determined in step S202 that no sufficient continuous emptyarea exists at the rear of the file system, the empty areas are arrangedby the file system or an application program, in step S204. Thereafter,a determination is again made as to whether a sufficient amount ofcontinuous empty area exists, in step S205. A supplementary spare areacan only be allocated in a physically contiguous area. If there is not abig enough physically contiguous area, then it is necessary tode-fragment the unused area. Thus, the empty area may be physicallymoved by the file system or application program. If there is asufficient amount of continuous empty area, step S203 of allocating thesupplementary spare area is performed. If the amount of continuous emptyarea is insufficient even after the arrangement of the empty areas, amessage “supplementary spare area cannot be allocated” is displayed, instep S206. Then, the process is terminated. If it is determined in stepS201 that a supplementary spare area is not required, the process isalso terminated.

Meanwhile, a small spare area for defect management can be allocated inspecial applications such as real time recording or the like, linearreplacement with respect to secondary defects is restrictedly made, andmost defects can be processed by the file system or application program.Also, it is preferable that secondary defects are processed by the filesystem or application program upon real time recording in order toobtain a minimum of transmission speed required by a correspondingapplication.

In this case, the recording and/or reproducing apparatus is alsorequired to detect defects and make minimum management with respect tothe detected defects. Here, the minimum management means managementusing SDL as to whether a generated defect has been linearly replaced.

For example, for defects generated during use of a disc that has defectmanagement information in which defect management using linearreplacement is not used for real time recording, only the start sectornumber of each defective block is recorded in a secondary defect list(SDL), information representing that the defective block has not beenreplaced is recorded in a forced reallocating masking (FRM) bit in anSDL entry representing whether the defective block has been replaced,and information representing that the defective block has not beenreplaced is recorded in the start sector number of a replaced block inthe SDL entry.

Further, FIG. 6 is a block diagram of a recording/reproducing apparatusfor implementing the present invention. The function of therecording/reproducing apparatus for recording/reproducing A/V(audio/video) data using the recordable and rewriteable recording mediasuch as the DVD-RAM is largely divided into recording, reproduction, andallocating and assigning spare areas.

During recording, an AV codec and/or a host interface 310compression-codes an externally applied AV signal according to apredetermined compression scheme and supplies size information for thecompressed data. A digital signal processor (DSP) 320 receives thecompressed A/V data supplied from the AV codec and/or the host interface310, adds additional data for error correction code (ECC) processingthereto, and performs modulation using a predetermined modulationscheme. A radio frequency amplifier (RF AMP) 330 converts the modulateddata from the DSP into a radio frequency (RF) signal. Then, a pickup 340records the RF signal supplied from the RF AMP 330 on a disk mounted ona turn table of the pickup 340. A servo unit 350 receives informationnecessary for servo control from a system controller 360 and stablyperforms a servo function for the mounted disk.

During playback of information data stored on the disk, the pickup 340picks up the optical signal from the disk having the information datastored therein, and the information data is extracted from the opticalsignal. The RF AMP 330 converts the optical signal into an RF signal,and extracts the servo signal for performing a servo function, andmodulated data. The DSP 320 demodulates the modulated data supplied fromthe RF AMP 330 corresponding to the modulation scheme used duringmodulation, performs an ECC process to correct errors, and eliminatesadded data. The servo unit 350 receives information necessary for servocontrol from the RF AMP 330 and the system controller 360, and stablyperforms the servo function. The AV codec and/or the host interface 310decodes the compressed A/V data supplied from the DSP 320 to output anA/V signal. The system controller 360 controls the overall system forreproducing and recording the information data from and on the diskmounted on the turn table of the pickup 340.

In allocating and assigning spare areas, the system controller 360recognizes one of the defective areas and registers the defect in thedefect management area (DMA) of the disk and allocates and assigns spareareas to the disk, including primary, secondary, and supplemental spareareas. In addition, the system controller 360 also preventsfragmentation of ECC blocks. The generation of fragmented ECC blocks isprevented by allocating and assigning additional spare areas to skip thefragmented ECC block to the beginning of an adjoining zone.

The system controller 360 and the DSP 320 handle processing the dataduring recording and reproduction, including recording and reproducingbased on a slipping and linear replacement performed on the disk.

In summary, when a disc is initialized, if there are more defectivesectors than the maximum number of entries in the PDL, the remainingdefective sectors will be replaced by linear replacement. If the numberof remaining defective sectors is larger than can be handled by theusable ECC blocks (the secondary spare area), then the supplementaryspare area shall be allocated. The primary spare area can handle themaximum number of PDL entries and the given number of SDL entries. Here,the primary spare area is used for slipping replacement and linearreplacement, the secondary spare area is a portion of the primary sparearea which is used for defects in the SDL by linear replacement, and thesupplementary spare area is only used for linear replacement whichcannot be covered by the primary spare area. Additional secondary spareareas cannot be allocated. However, the secondary spare area can existin a portion of the primary spare area as shown in FIG. 2A, or it canexist in each zone as shown in FIG. 2B. The remaining area of theprimary spare area after slipping replacement will automatically be usedas a secondary spare area.

Since the recording and/or reproducing apparatus cannot recognize defectcontents processed by the file system or an application program when acorresponding disc is again initialized and used for another purpose, itcan reinitialize the disc in disregard of generated defects.Accordingly, fast formatting cannot be performed, where the secondarydefects (stored in the SDL entry) are simply changed into a PDL entryand processed by slipping replacement, so that the recording and/orreproducing apparatus must manage defects even when the secondarydefects are managed by the file system or application program.Therefore, the generation or non-generation of defects must becontrolled in all cases using the SDL regardless of performance ornon-performance of linear replacement and the existence or non-existenceof a spare area for linear replacement.

As described above, the present invention removes a restriction on themaximum size of a defect that can be replaced by slipping replacement,without violating a restriction that even a large defect generated in agroup must be processed within the group, so that more efficientslipping replacement can be made. Also, the size of a spare area can beappropriately adjusted according to an application purpose, so that thedisc area can be more effectively utilized.

1. An optical data storage medium for use with a recording and/orreproducing apparatus, the medium comprising; a user data area on whichuser data is stored; and at least one spare data area used by theapparatus to replace defective units of said user data area; whereinsaid spare data area is used by the apparatus for replacement of saiddefective units of said user data area from rearmost units of said sparedata area.
 2. The optical data storage medium of claim 1, wherein thereplacement is performed in units of ECC blocks.